Balanced pressure pump



May 17, 1966 p, w, SCHLQSSER 3,251,305

BALANCED PRES SURE PUMP Original Filed May 17, 1963 .i 6 7 f 7 a i fig. 9.

A j INVENTOR.

PAUL W. SCHLOSSEP United States Patent 3,251,305 BALANCED PRESSURE PUMP Paul W. Schlosser, Chicago, IlL, assignor to Panther Pumps & Equipment Co., Inc., Chicago, 111., a corporation of Illinois Continuation of application Ser. No. 281,250, May 17, 1963. This application Apr. 12, 1965, Ser. No. 450,238 21 Claims. (Cl. 10344) This application is a continuation of application Serial No. 281,250, filed May 17, 1963, for a Balanced Pressure Pump, now abandoned.

The present invention relates broadly to fluid transfer mechanism; and more particularly to an improved pump for transferring fluids of several kinds and including difficult to transfer materials such as paints, corrosive liquids, sludges, abrasive slurries, etc., and includes structure for pumping same by means of a reciprocal diaphragm that is activated by a piston, or the like, through a fluid medium.

This invention is characterized in that a power driven pump including a piston movable in a predetermined path of travel causes apparatus to operate to supply the driving side of the diaphragm with fluid, preferably oil, and maintains a predetermined amount of oil between the piston and the side of the diaphragm acted upon by the piston. The fluid being transferred is caused during pumping to build up a pressure on the opposite side of the diaphragm, which pressure is opposed by an equal pressure on the driving side of the diaphragm to thereby maintain the differential pressure across the diaphragm at a predetermined low value.

The present invention is broadly related to my 00- pending application Serial No. 235,297, filed November 5, 1962, now Patent No. 3,207,080. This prior application is directed to structure for successively supplying and draining one side of a diaphragm with high pressure and sump pressure activating fluid to thus cause fluid to be pumped in accordance with changes in pressure in the driving fluid pressure, which causes corresponding pressure changes in the structure acting on the fluid being transferred whereby to balance the pressure differential across the diaphragm.

The present invention comprises an improvement of said prior mechanism in being substantially unitary structure wherein the piston which supplies-driving oil to the driving side of the diaphragm moves substantially in phase with the diaphragm. The face portions, or tops, of the pistons may 'be adjacent the diaphragm and complete a chamber therewith in combination with the cylinder Walls of the pump. The pump is adapted for ready installation and ready overhaul of parts that may fail. The structure is such that the cylinders can be formed substantially in alignment with each other which facilitates manufacture. All of the valving parts for maintaining the driving .oil can be readily serviced at the same time a diaphragm may be inspected or changed. It is a further advantage of this invention that the driving mechanism is unitary and capable of being withdrawn or inserted bodily as a sub-assembly into the pump housing with a minimum of difficulty.

Accordingly, it is a broad object of the invention to provide an improved fluid transfer mechanism.

Another object, in keeping with the above object is to provide a piston operated pressure balanced diaphragm pump.

It is a further object in keeping with each of the above objects to provide a double acting, substantially continuous flow fluid pump capable of handling corrosive and abrasive materials, which pump is compact in size and readily serviced.

It is a further object to provide an improved pressure balancing mechanism for driving diaphragms through a predetermined quantity of driving fluid.

It is a further object in connection with the next preceeding object to provide supply means for the driving oil to maintainthe quantity thereof at a predetermined desired quantity.

Other objects and advantages of this invention reside in the details of construction and the arrangement of parts and will be either obvious or pointed out in the following specification and claims interpreted in view of the following drawings, in which:

FIG. 1 is a diagrammatic view of a fluid transfer system incorporating the invention,

FIG. 2 is an end view of the pump,

FIG. 3 is a sectional View taken along line 3-3 of FIG. 2,-

FIG. 4 is a fragmentary sectional view taken on line 4-4 of FIG. 3,

FIG. 5 is a sectional view taken on line 5-5 of FIG. 3,

FIGS-6, 7, 8 and 9 are diagrammatic views of the pump in different positions showing valve function.

Before referring to details of construction, it is to be noted that this pump contains a body of oil 10, FIG. 5, which substantially fills the interior of the piston structure for purposes to be explained hereinbelow. Oil is not shown in the other views to avoid confusion with reference characters. Further, and particularly for high pressure use, other higher pressure lubricants may be desirable.

Referring first to FIG. 1, a pump 12 is driven by a motor 14 through a belt 15 and pulleys 16 and 17, however, gearing or direct drives may be used.

The pump 12 delivers fluid from a tank 18 at substantially atmospheric pressure to a user of the fluid 20 at a higher pressure up to several thousand p.s.i., for example. Check valves 21 serve to permit flow of fluid from the interior of the pump through pipes 22 to the user. Check valves 24 serve to prevent back-flow of fluid to the tank 18 through pipes 25. Pipes 27 connect the pumping chambers within the pump 12 to the tank and user of pressurized fluid. The valves 21 and 24 can be other than the check type generally indicated and could be incorporated into the heads of the pump 12 if desired. However, it is to be noted that the pipes 27 are preferably readily connected and disconnected so as to facilitate servicing of the pump parts in a manner to appear more fully below. I

Referring now to FIGS. 2, 3, 4 and 5, the pump 12 is built from a generally tubular casing 30 having a cylindrical internal bore 31. Because of the arrangement in alignment of the pistons, the bore 31 can conveniently be finished as by broaching same. Bosses 33 and 34 on right and left sides, respectively, of the casing 30 are bored in alignment to form bearing surfaces 35 and 36, respectively. The boss 33 is further tapped at 38 to receive a bushing 40 which is further bored at 41 to receive a pressed fit bearing 42. The bushing 30 is shaped to closely fit the bore 35 in the boss 33. An oil seal 44 is provided in the bushing 40 for fitting over the drive shaft 45. The boss 34 is counter-bored at 47 and recessed at 48 to retain an end bearing plate 49 and an oil seal 50 by a snap ring-52. The distal end 54 of the shaft 45 turns in a bearing 55 pressed into the bore 36 in the boss 34. A cam 58 is shown, FIG. 4, as comprising an outer race 60 riding on roller bearings 62 and an inner race 63 which may be welded or keyed to the shaft 54. The size of the hole 35 in the boss 33 is such that the cam 58 may be inserted therethrough.

The cam 58 bears on bottom surfaces 71 of bottom plates 65, only one plate being shown in section, to drive pistons 67 upwardly and downwardly as viewed in FIG.

3. As shown, the upper piston 67 is in its uppermost position at the end of a delivery stroke and the lower piston is in its lowermost position at the end of an intake stroke. Struts 70 connect the piston together and provide proper spacing for the bottom walls 71 of the bottom plate 65 a distance equal to the diameter of the outer race 60 of the cam 58. As best shown in FIGS. 3 and 4, as the cam 58 rotates through 360 degrees it will move the piston 67 from the position shown in FIGS. 3 and 4 down to the opposite position at 180 degrees of rotation and back to the positions shown in FIGS. 3 and 4. For extreme high pressure, beyond the service capability of roller bearings, plain bearings, not shown, may be used and a substantially square cross-head fitted over the inner race, or cam 63 and between the walls 71.

A pair of substantially identical flexible vinyl, or other suitable material, diaphragms 75 are shown secured between flattened surfaces 76 at the head ends of the pump 12 and flat surfaces 78 of caps 89 by reinforcing end plates 81 fitting around threaded inlet-outlet ports 82 and connected as by cap screws or through bolts 83, or the like, four of which are shown in FIG. 2. It is to be understood that for extremely high pressures, these cap plates 81 can be in the form of cups to further reinforce the caps 89 and to keep the size of such caps at a practicable minimum. It is presently preferred that these caps 89 be of nylon, or other suitable material, for resisting attack from the materials handled by the pump. As stated above, this pump is particularly adaptable for creating high pressures and for transferring corrosive and/or abrasive,-and the like, materials of many kinds. The diaphragms 75 and caps 80 can be suitably selected and sized accordingly.

The diaphragms 75, at their centers, are secured between a flat-head rivet 84 and the back of a flat-faced valve 85 to which the rivet 84 is secured through the diaphragm. The valve 85 is adapted to seat on the flatface 87 of a piston head 88, which head is held in sealed relationship in a counterbore in the piston 67 by suitable means such as a snap ring 90. The valve 85 is shown as closing a port 92 on one side. The port 92 is further closed on its opposite side by a reed-valve 95 secured, as by screws 94, to the inside of the plate 88. The reedvalve 95 has a small metering orifice 96 therethrough and in communication with the port 92 for a purpose to be pointed out more fully hereinbelow.

As mentioned above, the oil 11), FIG. 5, substantially fills the interior of the pump 12. This oil is supplied through a port 99 in a boss 100 at the top of the body 30, FIG. 2, which port 99 is closed by a screw plug Hi1 having a breather seal 102 therein, whereby tomaintain substantially atmospheric pressure within the housing 30. Oil will flow through ports 194 in the pressure plates 65, FIG. 3, to keep the pistons substantially full of oil at all times. This oil passes through the metering orifice 96 to the chamber 108 formed by the piston walls 31 adjacent the diaphragm 75 -and the top 87 of the pistons 67. O-rings 106 are placed in peripheral grooves in the piston 67 to provide an oil seal to maintain oil in the chamber 108 whereby pressure is transferred from the pistons through the fluid to the bottoms of the diaphragms 75 to the fluid in the pumping chamber 109 during a pressure stroke of the pump 12.

Operation Referring now to FIGS. 6 through 9, and first to FIG. 6, the piston 67 is shown as descending to its lowermost position. A slight clearance 105 is present uncovering the port because the diaphragm '75 is at its maximum extended position and is accordingly urged to the position shown bysub-atmospheric pressure of fluid introduced into the port 8% and atmospheric pressure within the housing 30. The reed-valve 95 will be closed and atmospheric pressure acting on the oil within the piston 67 will force same to flow upwardly through metering orifice 96 to the chamber 108 above the piston and below the diaphragm 75. Accordingly, a small amount of oil will be metered into this chamber at this portion of the stroke of the piston 67.

As shown in FIG. 7, the piston 67 is traveling upward and the reed-valve 95 will be urged downwardly by pressure exerted upon any excessive fluid present in the chamber 1.68 below the diaphragm 7S and the upper face of the piston 67 until the valve closes. After the valve 85 closes, the diaphragm 75 will move upward to expel fluid from the pumping chamber 169 of the pump 12. At this portion in the pumping cycle, the pressures on both sides of the diaphragm in both the pumping chamber 109 and the motion transferring chamber 108 will be substantially equal to each other inasmuch as each chamber preents substantially the same diaphragm area to the different fluids.

As shown in FIG. 8, the piston 67 has traveled further upward to drive fluid out of the top of the pump. At this point in the pumping cycle, a small amount of driving fluid below the diaphragm 75 may have leaked away around the piston, or back through the head of the piston, or out from beneath the valve 35. However, fluid pressures on both sides of the diaphragm will remain equal.

In FIG. 9 the piston 67 is shown as begining its suction stroke and because of the above mentioned leakage of driving fluid from beneath the diaphragm, there will again be a slight clearance 105 between the valve 85 and the top surface 87 of the piston. Accordingly, driving fluid can again pass through the orifice 96 at a metered rate to replenish the supply of the pressure transfer fluid.

The above operation cycle will repeat itself for each revolution of the drive shaft 45 and thus the fluid in the driving chamber is maintained in a predetermined volume whereby to cause differential pressure across the diaphragm to remain substantially the same at all times regardless of pressure supplied by the pump to the pumped fluid in the pumping chambers 109.

The above disclosure has shown only two pistons driven by a single cam. It is believed to be obvious, when less fluctuation in pressure of the delivered fluid is desired, or more capacity, or the like, that more than two pistons can be used by simply adding additional housings 30 and accordingly extending the shaft 45 and providing additional cams 58 to drive multi-cylinder devices. It is further to be noted that only a single action and not a double action pump can be provided.

The present pump 12 may be readily overhauled and repaired. The pipes 27, FIG. 1, are removed, bolts 83 removed and the bushing 40 withdrawn, which latter permits the cam 58 and drive shaft 45 to be withdrawn as a unit. The heads 80 can be removed to give access to the diaphragms 75 and the piston 67 can then be withdrawn. The snap rings permit ready removal of the piston top plates 88 to service or inspect the reed-valves 95. The bearings 42 and 55 can also be readily driven out for replacement, if required.

In view of the above disclosure, several modifications and adaptations of the invention may occur to others skilled in the art. Accordiigly, I wish not to be limited in this invention only to the specific embodiment shown and described but by the scope of the following claims.

3. The pump of claim 2, said valve means including means forming a second substantially larger orifice than said metering orifice.

4. The pump of claim 3, said orifices being substantially in alignment with respect to each other.

5. The pump of claim 4, said driving member carrying at least one of said orifices.

6. The pump of claim 1, said diaphragm carrying a second portion of said valve means cooperable with said ported part movably carried by said driving member.

7. The pump of claim 6, said ported part including a valve port, and said second portion being a valve memher.

8. The pump of claim 7, and means in said valve means forming a third portion thereof.

9. The pump of claim 8, said third portion including means forming a fluid metering orifice.

10. The pump of claim 9, said metering orifice being operable to cause a first rate of flow in one sense and a second rate of flow in another sense.

11. The pump of claim 1, said driving member being power driven piston means, and said housing forming cylinder means therefor.

12. The pump of claim 11, said piston means having end portions forming a pair of driving means, one of said end portions being cooperable with said driving chamber, and the other ofsaid end portions being cooperable with a second driving chamber, and means forming second driving and pumping chambers.

13. The pump of claim 11, and driving means for said piston means including means for reciprocating same.

14. The pump of claim 13, said driving means being a driven cam, and cam bearing surfaces connected between said cam and said piston means for causing reciprocation therefor by said cam.

15. In fluid transfer apparatus a piston operated diaphragm secured in a chamber in the apparatus to form a first variable volume fluid transfer chamber and a sec ond variable volume fluid chamber closed by said piston, of means including ported valve means carried by said piston and valve means carried by said diaphragm for maintaining the volume of fluid in said second chamber substantially constant during reciprocal movement of said piston.

16. In a fluid transfer device a piston operated diaphragm secured in a chamber in said apparatus to form a first variable volume fluid transfer chamber and a second variable volume fluid chamber closed by said piston, of fluid pressure actuated control means including ported valve means carried by said piston and valve means carried by said diaphragm for maintaining the volume of fluid in said second chamber substantially constant during reciprocal movement of said piston.

17. In a fluid transfer machine, the combination with a piston operated diaphragm secured between Walls of the machine to form a first variable volume fluid transfer chamber and a second variable volume fluid chamber closed by said piston, of fluid pressure actuated valve means including ported means carried by said piston and means driven by said diaphragm for controlling the volume of fluid in said second chamber and causing the volume to be less variable than the volume of fluid in said first chamber.

18. In a fluid transfer machine, the combinationwith diaphragm divided variable volume fluid chambers having power operated means for causing one of said chambers to be changed in volume by movement of fluid in a second of said chambers, of means having at least one part driven by said diaphragm and at least one other ported part carried by said power operated means for maintaining a substantially constant volume of fluid in said second chamber during operation of said machine.

19. In a piston driven diaphragm pump, valve means for maintaining a substantially constant volume of driving fluid between said piston and said diaphragm, said valve means including one valve ported part carried by said piston and anothervalve part carried by said diaphragm.

20. In a pump substantially as set forth in' claim 19, metering valve means for regulating the rate of increase of volume of said driving fluid.

21. In a piston driven diaphragm, a chamber for a driving fluid, a movable piston in the chamber, a port in the piston, a diaphragm in the chamber, a valve head for said port for controlling flow through said port during a predetermined phase of movement of said piston, a reed valve carried by the piston for controlling flow through said port during a predetermined phase of movement of said pistomand means for supplying fluid to the interior of said piston for flow through said port.

References Cited by the Examiner UNITED STATES PATENTS 1,301,485 4/1919 Mueller 10344 2,303,597 12/1942 Adelson 10344 2,919,650 1/1960 Wiggermann 103-150 X 2,948,223 8/1960 Mashinter 103-44 FOREIGN PATENTS 6,657 1894 Great Britain. 586,862 4/1947 Great Britain.

ROBERT M. WALKER, Primary Examiner. DONLEY J. STOCKING, Examiner. 

1. IN A PUMP, THE COMBINATION WITH A DIAPHRAGM SECURED IN A HOUSING FOR FORMING PUMPING AND DRIVING FLUID CHAMBERS THEREIN AND HAVING A MOVABLE DRIVING MEMBER COMPLETING THE DRIVING CHAMBER, OF VALVE MEANS FOR MAINTAINING A SUBSTANTIALLY CONSTANT VOLUME OF FLUID IN SAID DRIVING CHAMBER, SAID VALVE MEANS HAVING AT LEAST ONE PORTED PART MOVABLY CARRIED BY SAID DRIVING MEMBER AND AT LEAST ONE OTHER PART DRIVEN BY SAID DIAPHRAGM. 